Protein base adhesive compositions with improved water resistance



United States Patent 3,397,071 PROTEIN BASE ADHESIVE COMPOSITIONS WITH IMPROVED WATER RESISTANCE Herman Knieriem, Jr., Midland, Mich., assignor to The Dow Chemical Company, Midland, Mich., a corporation of Delaware No Drawing. Original application Mar. 14, 1962, Ser. No. 179,764, now Patent No. 3,264,243, dated Aug. 2, 1966. Divided and this application Mar. 7, 1966, Ser. No.

4 Claims. (Cl. 106154) I ABSTRACT OF THE DISCLOSURE An adhesive composition comprised of a vegetable protein base adhesive and an amount suflicient to improve the water resistance of an alkyl aryl sulfonate having the formula I (S 3 )m Y v I- J (halogen):

wherein the substituents have the meanings set forth below.

This application is a divisional of Ser. No. 479,764, filed Mar. 14, 1962, now Patent No. 3,264,243, dated Aug. 2, 1966.

The present invention pertains to new adhesive compositions. More particularly the present invention concerns vinyl adhesives and vegetable protein adhesives having markedly improved Water resistance.

It has now been found that the water resistance of vinyl adhesives and vegetable protein adhesives can be improved by adding to conventional adhesives of the classes named an alkylated phenyl ether sulfonate having the general formula wherein alkyl represents an alkyl radical having from 8 to 18 carbon atoms, p is an integer from 1 to 2; halogen represents chlorine or bromine; d represents an integer from 0 to 1, M represents an alkali or alkaline earth metal, and m represents an integer from 1 to 3. Thus, there is included the alkali metal alkylated phenyl ether sulfonates having from 8 to 18 carbon atoms in the alkyl chain, the alkali metal dialkylated phenyl ether sulfonates, the alkali metal alkylated phenyl ether disulfonates, the alkali metal dialkylated phenyl ether disulfonates, and their chlo-ro and bromo derivatives, and the like, and the alkaline earth alkylated phenyl ether sulfonates, the alkaline earth dialkylated phenyl ether sulfonates, the alkaline earth alkylated phenyl ether disulfonates, and the like.

The classes of adhesives which exhibit this markedly improved property when modified in the aforesaid manner are the vegetable protein adhesives which include adhesives based on soybean protein, zein protein, and the like, as well as the vinyl adhesives which include polyvinyl acetate, polyvinyl butyral, polyvinyl ethers and copolymers of polyvinyl acettae and polyvinyl chloride, and the like.

The modifying agents which can be employed in accordance with the present invention are the alkylated (halogen)a 3,397,071 Patented Aug. 13, 1968 phenyl ether sulfonate alkali metal salts and alkaline earth metal salts such as for example: monochlorododecylphenyl ether sulfonate, sodium salt; monobromododecyl phenly ether sulfonate, potassium salt; dodecylphenyl ether 5 sulfonate, sodium salt; nonylphenyl ether sulfonate, potassium salt; octyldecylphenyl ether 'sulfonatc, sodium salt; monochlorododecylphenyl ether sulfonate, calcium salt; monobromodidodecylphenyl ether sulfonate, magnesium salt; and the like. Thus one can employ any alkali metal or alkaline earth metal C through C monoor dialkyl phenyl ether mono-, dior trisulfonate, e.g., lithium, sodium,, potassium, rubidium, cesium, calcium, magnesium, strontium, barium salts of the respective acids although the sodium, potassium, calcium, and magnesium salts are preferred since they are more easily prepared from more readily available and less expensive materials.

The following examples illustrate the present invention but are not to be construed as limiting:

Example 1 A protein base adhesive was prepared according to manufacturers mixing direction in the following manner: 100 parts of a vegetable protein (soybean protein) aqueous adhesive (Casco W-l69l manufactured by Borden Company), 180 parts of water and 5 parts of Dowicide 7 (a phenolbase fungicide manufactured by the Dow Chemical Company) were mixed for 5 minutes and then 185 parts of water at 5 060 F. were added and mixing continued for 2 to 3 minutes. Lime in water (12 parts lime and 24 parts water) was added and the mixture stirred for 5 minutes, then 25 parts of sodium silicate and 1.75 parts of carbon disulfide in carbon tetrachloride (75:25 ratio) were added and stirring continued for 5 minutes. Thereafter 14 parts of 50% NaOH solution were added and the resulting mixture blended on a Waring Blend or until smooth and free from lumps. Various percentages of dodecylphenyl ether monosulfonate sodium salt were added to aliquot portions of the adhesive and the modified adhesives spread on panels 6" x 6" x 4;" to make 3-ply panel board. The glued panels were placed in a cold press for minutes at a pressure of 200 psi, then cured under atmospheric pressure and room temperature for 24 hours.

To test for water resistance, 1" x 3% samples were cut from each 6" x 6" panel and immersed in cold water. If after 8 hours the strips were still bonded, the water was raised to boiling and soaking continued. The time for delamination is recorded in the following table. A panel glued with an adhesive having no dodecylphenyl ether sulfonate sodium 'salt, was also run as a control and the results of the immersion test are also recorded.

Percent by Weight of Total Time in Minutes Dodecylphenyl Ether Before Delamination Sod1um Sultanate (Average of 3 Samples) Introduced as a 45% aqueous solution in an amount sufficient to przoidatthle indicated amount of the active ingredient.

on to Examples 9l1 Unbleached kraft paper was cut into 1" x 4" strips.

Polyvinyl acetate adhesive (a commercial adhesive obtained from Williamson Adhesives Company) containing various amounts of additive was applied to 1 sq. inch of the end of one strip. Another 1" x 4" strip was placed with 1 sq. inch of its end imposed upon the glued area. The net result being a sample 7" long with 1 sq. inch of glued area. This sample then was pressed for 30 minutes under a 1 kg. weight. The weight was then removed and the strip allowed to cure for 72 hours. The sample was then weighted and suspended in boiling water. If delaminationhad not occurred within 8 hours the sample was suspended in cold water overnight, and boiling was resumed the following day. The time elapsed un- HIGH HUMIDITY BOND STRENGTH TESTS Shear strip specimens were stored in a tropical chamber, 95% humidity at 80 F., for three days. The samples were then dried for hours, and tested on the Instron machine. The results are set forth in the summary table below.

SUMMARY The following table shows the improvement in the water resistance and the bond strength of a polyvinyl acetate adhesive that may be obtained using 1.5% of the Na salt of dodecylphenyl ether sulfonate.

Ex. No. Test PVAc Blank PVAc+1.5% Percent Average Average Improvement 12 Water Resistance 362 1, 599 331 13 Dry Bond Strength:

Shear Pressure 205 257 25. 4 Percent Wood Failure-.. 43 66 53. 5 14 Wet Bond Strength:

Shear Pressure 141 210 49. 0 Percent Wood Failure. 22 54 61. 6 16 Humidity Bond Strength:

Shear Pressure 152 201 32. 2 Percent Wood Failure 17 61 259. 0

til the sample completely separated is recorded as the Example 16 delamination time in the table below:

Percent by Weight of Total Time in Minutes Examples 12-15 There was added to a polyvinyl acetate emulsion adhesive (hereinafter referred to as PVAc) (obtained from Shawinigan Resins Corporation) 1.5 by weight of dodecylphenyl ether sulfonate sodium salt. This adhesive composition was" used to prepare 3 ply board from 12" x 12" x /8" matched panel rotary cut Douglas fir veneer. The panels were prepared in a manner similar to that described in Example 1. The weight of glue employed was determined by weighing the samples before and after gluing and was found to be about 58 pounds per 1000 square feet of double glue line. The panels were cold pressed under 200 lbs./in. pressure for minutes and then cut into 1" x 3% shear strips and used in the following tests. Blank specimens were prepared employing the PVAc adhesive without any additive.

WATRE RESISTANCE TEST The water resistance of the adhesive system was evaluated by completely immersing the shear strips in water at room temperature, and measuring the time required for the strips to delaminate. A test tube clamp was attached to the end of the shear strip, so that the strip would remain erect, completely beneath the surface of the water for the duration of the tests. The delamination time shown in the following table summary and the percent improvement of the adhesives water resistance containing the additives are set forth.

DRY BOND STRENGTH TEST In this test, the samples are clamped firmly in the jaws of the Instron machine test apparatus. The machine is started and the jaws separated at a rate of 0.1 inch per minute. The data obtained is set forth in the summary table below.

WET BOND STRENGTH TESTS Shear strip specimens were soaked in water at room temperature for 30 minutes prior to testing in the manner described in the Dry Bond Strength Test. The results are set forth in the summary table below.

A formulation was prepared as follows:

100 g. polyvinyl acetate adhesive (commercial preparation obtained from Williamson Adhesives Company) 4 g. of 25% solution of surface active material.

Thus the adhesive compositions contain 1% by weight of active surfactant.

The so-prepared adhesives are cast into a 20 mil thickness film 5 inches wide perpendicular to the length of an 18 x 5 /2 inch plate glass panel. The films were allowed to age for 24 hours. The film and glass were then placed in the trough or a Gardner Straight-line Scrubber. A photographic grade cellulose sponge evenly wetted with 25 ml. of deionized water was inserted into the scrubbing attachment and the apparatus started. Between 60 and 70 strokes, 1 ml. of deionized water was added to the surface of the film via a burette. Another 1 ml. increment was added between and strokes, and 18 ml. in 2 ml. increments was added between and 200 strokes. The test was stopped when the film disintegrated or when a prescribed number of strokes was completed.

Strokes to failure of Surfactant: film, two replicates Blank (4 g. H O added to make up to weight of compositions and surfactant) 42, 41 Alkylbenzene sulfonate 178,68 Ca salt of dodecylphenyl ether disulfonate 406, 457 Mg salt of dodecylphenyl ether disulfonate 446,433

Iclaim:

1. An improved, water resistant adhesive comprising a vegetable protein base adhesive and an amount of an alkyl aryl sulfonate having the formula number from 17 to 35, d represents an integer from 0 to 1, M represents a member selected from the group con- (Halogen) dL 5 6 sisting of alkali metal and alkaline earth metals and m References Cited represents an integer from 1 to 3 effective to improve the UNITED STATES PATENTS water resistance of the adhesive when set.

2. A composition as set forth in claim 1 wherein said 264,243 8/1966 Knlenem 260-295 sulfonate is sodium dodecylphenyl ether sulfonate. 5 3,245,914 4/1966 Stemhauer et 252106 3. A composition as set forth in claim 1 wherein said 2,887,395 5/1959 Rowe et sulfonate is sodium dodecylchlorophenyl ether sulfonate. 4. The adhesive defined in claim 1 wherein the adhesive JAMES SEIDLECK Pnmary Examme" base is soybean protein. T. MORRIS, Assistant Examiner. 

